1. Field of the Invention
The present invention relates generally to optoelectronic microelectronic products. More particularly, the present invention relates to image sensor optoelectronic microelectronic products.
2. Description of the Related Art
Within the general art of microelectronic product fabrication there exist purely electronic microelectronic products whose operation is based solely upon electrical signal storage and processing characteristics of purely electronic microelectronic devices and microelectronic circuits formed upon a microelectronic substrate. Examples of such purely electronic microelectronic products typically include, but are not limited to, semiconductor products and ceramic substrate products. Similarly, there also exist within the general art of microelectronic product fabrication microelectronic products whose operation is based upon a codependent transduction, storage and/or processing of optical and electrical signals while employing optoelectronic microelectronic devices formed upon a microelectronic substrate. Examples of such optoelectronic microelectronic products typically include, but are not limited to: (1) solar cell products; and (2) image array products such as but not limited to: (a) sensor image array products; and (b) display image array products.
While optoelectronic products are thus quite common in the microelectronic fabrication art, optoelectronic products are nonetheless not entirely without problems.
In that regard, it is often difficult to fabricate optoelectronic products with enhanced optical performance.
It is towards the foregoing object that the present invention is directed.
Various optoelectronic products having desirable properties, and methods for fabrication thereof, have been disclosed in the microelectronic product fabrication art.
Included among the optoelectronic products but not limiting among the optoelectronic products are optoelectronic products disclosed within: (1) Ooi et al., in U.S. Pat. No. 5,283,675 (a liquid crystal display optoelectronic product with an electrode having a concave and convex undulating surface); (2) Kim et al., in U.S. Pat. No. 6,100,953 (a liquid crystal display optoelectronic product with a color filter layer having a concave surface); and (3) Endo et al., in U.S. Pat. No. 6,255,640 (an image sensor optoelectronic product with a color filter layer having a protuberance).
The teachings of each of the foregoing references are incorporated herein fully by reference.
Desirable are additional optoelectronic products with enhanced optical performance.
It is towards the foregoing object that the present invention is directed.
A first object of the invention is to provide a method for forming an optoelectronic product.
A second object of the invention is to provide a method in accord with the first object of the invention, wherein the optoelectronic product is formed with enhanced optical performance.
In accord with the objects of the invention, the invention provides a method for forming an optoelectronic product.
To practice the method of the invention, there is first provided a substrate having formed therein a photoactive region. There is then formed over the substrate including the photoactive region a planarizing passivation layer. There is then masked the planarizing passivation layer to form a masked planarizing passivation layer which leaves exposed a portion thereof registered with the photoactive region. There is then etched isotropically the masked planarizing passivation layer to form an isotropically etched planarizing passivation layer having formed therein a concavity registered with the photoactive region. Finally, there is then formed over the isotropically etched planarizing passivation layer and registered with the concavity a microlens layer having a convex surface.
The method of the invention contemplates in part a microelectronic product which may be formed in accord with the method of the invention.
The present invention provides a method for forming an optoelectronic product, wherein the optoelectronic product is formed with enhanced optical performance.
The invention realizes the forgoing object by forming registered with a photoactive region within a substrate a concavity within a planarizing passivation layer formed over the substrate. The concavity is formed incident to isotropic etching of the planarizing passivation layer when properly masked. In turn, a microlens layer having a convex surface is formed over and registered with the concavity. Thus, the invention provides an optoelectronic product having a concave lensing layer registered with a convex lensing layer to provide the optoelectronic product with enhanced optical performance.